Electronic meters of the flat-bed printer type are well-known and are described for example in U.S. Pat. No. 4,579,054, issued to Buan, et al., which shows a stand-alone electronic mailing machine in which the electronic postage meter forms an integral part of the device. Aspects of such a stand-alone mailing machine are described in U.S. Pat. Nos. 4,535,407 and 4,523,523 among others.
Of particular concern in postage meters and mailing machines developed for high throughput is the speed with which the printwheels can be set to a new value. U.S. Pat. No. 4,034,669 teaches the use of a separate stepper motor for each printwheel in the printdrum of a postage meter of the rotary press type. U.S. Pat. No. 4,398,458 shows a setting device for the printwheels in a print drum in which separate stepper motors are used for each printwheel. U.S. Pat. No. 4,541,053 describes a method for the parallel setting of printwheels using a particular drive arrangement for the stepper motors. While the devices shown in these patents provide additional economy and speed because they operate in parallel, the printwheels are set by racks and a pinion and must be set only when the drum is in a predetermined position.
U.S. Pat. No. 4,367,676 issued to Clark discloses a selection mechanism for a rotary print drum meter which may be used when the drum is at rest or in motion. One embodiment is shown in which separate motors are used to drive each setting wheel. It is suggested therein that the arrangement allows for shortest path setting. U.S. Pat. Nos. 4,608,923 and 4,658,722 issued to Muller show other printwheel setting devices for rotary drum printing postage meters. The devices described therein are operated for the sequential setting of each printwheel. The use of absolute encoding taught therein allows the elimination of any stops on the gears to enable shortest path setting.
While each of these devices may work well in its intended manner, each is not suitable for operation in a flat bed letter press postage meter. Only Clark teaches setting during movement of the printdrum and the setting mechanism requires a complex gearing arrangement to enable rotation of the drum while maintaining the printwheels fixed.